NTP multicast mode configuration example

As shown in Figure 40, Switch C functions as the NTP server for multiple devices on different network segments and synchronizes the time among multiple devices.

• Configure Switch C's local clock as a reference source, with stratum level 2.

• Configure Switch C to operate in multicast server mode and send multicast messages from VLAN-interface 2.

• Configure Switch A and Switch D to operate in multicast client mode and receive multicast messages through VLAN-interface 3 and VLAN-interface 2, respectively.

1. Assign an IP address to each interface, and make sure the switches can reach each other, as shown in Figure 40. (Details not shown.)

2. Configure Switch C:

   # Enable the NTP service.

   <SwitchC> system-view
   [SwitchC] ntp-service enable
   

   # Specify the local clock as the reference source, with stratum level 2.

   [SwitchC] ntp-service refclock-master 2
   

   # Configure Switch C to operate in multicast server mode and send multicast messages through VLAN-interface 2.

   [SwitchC] interface vlan-interface 2
   [SwitchC-Vlan-interface2] ntp-service multicast-server
   

3. Configure Switch D:

   # Enable the NTP service.

   <SwitchD> system-view
   [SwitchD] ntp-service enable
   

   # Configure Switch D to operate in multicast client mode and receive multicast messages on VLAN-interface 2.

   [SwitchD] interface vlan-interface 2
   [SwitchD-Vlan-interface2] ntp-service multicast-client
   

4. Verify the configuration:

   Switch D and Switch C are on the same subnet, so Switch D can do the following:

   • Receive the multicast messages from Switch C without being enabled with the multicast functions.

   • Synchronize to Switch C.

   # Verify that Switch D has synchronized to Switch C, and the clock stratum level is 3 on Switch D and 2 on Switch C.

   [SwitchD-Vlan-interface2] display ntp-service status
    Clock status: synchronized
    Clock stratum: 3
    System peer: 3.0.1.31
    Local mode: bclient
    Reference clock ID: 3.0.1.31
    Leap indicator: 00
    Clock jitter: 0.044281 s
    Stability: 0.000 pps
    Clock precision: 2^-18
    Root delay: 0.00229 ms
    Root dispersion: 4.12572 ms
    Reference time: d0d289fe.ec43c720  Sat, Jan  8 2011  7:00:14.922
   

   # Verify that an IPv4 NTP association has been established between Switch D and Switch C.

   [SwitchD-Vlan-interface2] display ntp-service sessions
          source          reference       stra reach poll  now offset  delay disper
   ********************************************************************************
    [1245]3.0.1.31        127.127.1.0        2     1   64  519   -0.0 0.0022 4.1257
   Notes: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured.
    Total sessions: 1
   

5. Configure Switch B:

   Because Switch A and Switch C are on different subnets, you must enable the multicast functions on Switch B before Switch A can receive multicast messages from Switch C.

   # Enable IP multicast routing and IGMP.

   <SwitchB> system-view
   [SwitchB] multicast routing
   [SwitchB-mrib] quit
   [SwitchB] interface vlan-interface 2
   [SwitchB-Vlan-interface2] pim dm
   [SwitchB-Vlan-interface2] quit
   [SwitchB] vlan 3
   [SwitchB-vlan3] port ten-gigabitethernet 1/0/1
   [SwitchB-vlan3] quit
   [SwitchB] interface vlan-interface 3
   [SwitchB-Vlan-interface3] igmp enable
   [SwitchB-Vlan-interface3] igmp static-group 224.0.1.1
   [SwitchB-Vlan-interface3] quit
   [SwitchB] igmp-snooping
   [SwitchB-igmp-snooping] quit
   [SwitchB] interface ten-gigabitethernet 1/0/1
   [SwitchB-Ten-GigabitEthernet1/0/1] igmp-snooping static-group 224.0.1.1 vlan 3
   

6. Configure Switch A:

   # Enable the NTP service.

   <SwitchA> system-view
   [SwitchA] ntp-service enable
   

   # Configure Switch A to operate in multicast client mode and receive multicast messages on VLAN-interface 3.

   [SwitchA] interface vlan-interface 3
   [SwitchA-Vlan-interface3] ntp-service multicast-client
   

7. Verify the configuration:

   # Verify that Switch A has synchronized to Switch C, and the clock stratum level is 3 on Switch A and 2 on Switch C.

   [SwitchA-Vlan-interface3] display ntp-service status
    Clock status: synchronized
    Clock stratum: 3
    System peer: 3.0.1.31
    Local mode: bclient
    Reference clock ID: 3.0.1.31
    Leap indicator: 00
    Clock jitter: 0.165741 s
    Stability: 0.000 pps
    Clock precision: 2^-18
    Root delay: 0.00534 ms
    Root dispersion: 4.51282 ms
    Reference time: d0c61289.10b1193f  Wed, Dec 29 2010 20:03:21.065
   

   # Verify that an IPv4 NTP association has been established between Switch A and Switch C.

   [SwitchA-Vlan-interface3] display ntp-service sessions
          source          reference       stra reach poll  now offset  delay disper
   ********************************************************************************
    [1234]3.0.1.31        127.127.1.0        2   247   64  381   -0.0 0.0053 4.5128
   Notes: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured.
    Total sessions: 1